Look at this thread here:
You should be able to convert the XDA localization to Japanese.
FYI - The XDA comes in two models as it is only a dual band device - 900/1800 MHz bands or 900/1900 MHz bands
Make sure the frequency matches your area's/provider's operational frequency.
Current/Active: Inspire 4G / Nexus 1 / Dell Streak / EeePad Transformer
Reserve Duty: 3125 / MPX200 / Tilt
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